Membrane Fluidity And Regulation Flashcards
What if the membrane is too fluid?
It will not serve as a barrier and will fall apart
What if the membrane is too solid?
It will not permit intergral proteins to flex and carry out their functions
How can cells regulate the fluidity of membranes?
More or fewer, longer or shorter unsaturated FA chains and
Higher concentration of phospholipids with _______, ________ FA chains are more fluid and pack less tightly.
short, unsaturated
Higher concentration of phospholipids with _______, ________ FA chains are less fluid and pack more tightly.
long, saturated
What will PM become in low temps?
Less fluid (more solid)
What will PM becomes in high temps?
More fluid (not solid enough)
Hydrophobic interior
Major barrier for molecules crossing a plasma membrane
What is PM permeable to?
Nonpolar molecules
What is PM semi-permeable to?
Small polar molecules
What is PM not permeable to?
Large polar molecules or ions
Diffusion
The movement of molecules across the membrane from high concentration to low concentration and does not require cellular energy
Active Transport (Anti-Diffusion)
The movement of molecules across the membrane from low concentration to high concentration and require cellular energy
